Dynamo-electric generator.



F. EICHERT. DYNMO ELECTRIC GENERATOR. APPLIQATION man MAR. 18, 1912.

70 l f ttof'hgy Patenteiwuly 6,1915@ y tion wheel in contact with one ofvrthe road .wheels `rarrz momenti', or BERLIN, GERMANY,

saumon, or comme. GERMANY.

FHCE@ Assrencnro THE FIRM or GnnIF AND Dynamo-ELECTRIC Genaueres.

To all whom 'it may concern.

` Be it known that I, FRITZ EICHERT, a sub ject of the German Emperor, residing at Berlin, in Germany, have invented certain new and useful Improvements in Dynamo- Electric Generatbrs, of which the following Vthe current is used for feeding electric glow lamps, the dynamo armature being, 1n the case of bicycles, commonly driven by a fric- If ,electric generators of this descripti'on are designed to supply sufficient current atcomparatively low speeds of the prime mover, the pressure of current is liable to becomevtoo high for the lamps at the higher speeds. If the generator is designed to supply the proper current at the higher speeds, the lamps will be dim when the veloci ede or vehicle slows down. l

The object of the present invention is to provide an improved automatic device for regulating the current furnished by the gen erator.' To this end I use a device whereby a coil on the armature is automatically short-circuited upon itself when a certain speed is reached, so that the currentgenerate'd in this coil has a `deanagnetizing effect which weakens the current supplied to the external circuit. Moreoveigif the shortcircuited coil is part of the normal armature winding, the short-circuiting' reduces the number of ampere-turns whereby current is supplied to the external circuit.

-The .automatic device which use is a centrifugal contact device 'or switch in a shunt connected to the armature coil.

The invention is illustrated in the accomh panying drawing in which Figures 1 and 2 are respectively an elevation of the generator, and a diagram of the armature coil, illustrating in a purely dia- 2, the Winding `on the armature comprises two sections 8 and 9 in `series with each other. The end 10 of the winding is joined Specification of Letters Patent..

to the lamp circuit, whereas the other end is connected to the machine at 11, and'thence to the lamp circuit. The brushes for supplyl' ing current from the armature 7 to .the outer circuit are omitted in the drawing for the sake of clearness. The junction 12 of the two sections' 8 and 9 is connected with a' contact 13 insulated from the armature.

lVhen the centrifugal force of the rotating armature is sufficiently high to cause the lever 15, pivoted at 14 to the amature, to

Patented J uly 6', 1915.` Application fue@ March 1s, 1912, serial No, 684,567.

overcome the pull of the spring 16, and move i asindicated by the arrow, the section 9 isshort circuited by the lever 15 making contact with the contact 13, so that the electromotive force of the generator is reduced. The current in the short circuit of coil section' Q'also has a de-magnetizing effect. weakening the potential diderence between 10 and 11, and this effect increases with the said current, that is to saylwith the sped of the armature. The coil'section 9 assists in the production of useful current until it is short circuited Figs. 3, 4 and 5 are respectively a side elevation, partly in section, an end elevation, 'and a plan view of one form of the centrifugalswitch which I may use. The drum armature a has in one pole-piece a groove, in which is embedded a springy metal strip 7), held in position by a screw-c in such manner that one end of the strip can swing outal ward under the influence of centrifugal over one edge of the pole-piece and has a lateral extension normally located' at a certain distance from a pin d inserted in the end of the armature and insulated from the latter. When the metal strip b moves outward by centrifugal force, the lateral extension thereof touches the pin d. vThe strip is connected to one terminal of the coil section tobe short circuited, and the pin d is connected to the other terminal. 1

1What I claim as my invention and desire tol secure by States is 1. In a dynamo electric generator the combination of an armature, two coil sections on said armature, one of said coil sections .being arranged to weaken the fieldy of the generator by the magnetic effect pf current flowing in said coil section, and a switch on said armature actuatable by .cenxtrifugal force, adapted-to short circuit said Letters Patent inthe United A electrically connected to the junction between said coil sections, and a switch lever carried by said' arma-ture, electrically connected to the end of onsy of'sald .coll sections and arranged to be thrown against said con` tact by centrifugal force at a predetermined armature speed.

In witness whereof I have signed thls specification in the presence` of two wit-v 15 nesses.

FRITZ EICI-IERT.

Witnesses: I i

HENRY HAsPl-m, Wo EMAR HAUPT, 

